Control device and method for controlling element substrate

ABSTRACT

An element substrate is provided with a fuse memory configured to store information in response to having a voltage applied thereto, a first switch configured to switch whether or not to energize the fuse memory, a resistance element, a second switch configured to switch whether or not to energize the resistance element, a first node connected to the fuse memory and the resistance element, and a second node configured to supply power to the first node from outside. Regarding the element substrate, electric charge that remains at the first node is discharged by allowing, before allowing the first switch to energize the fuse memory, the second switch to energize the resistance element from the first node.

BACKGROUND OF THE DISCLOSURE Field of the Disclosure

The present disclosure relates to a control device and a method forcontrolling an element substrate.

Description of the Related Art

As disclosed in Japanese Patent Laid-Open No. 2006-15736, a print headof an inkjet printing apparatus has, in addition to a heater fordischarging ink, an element substrate provided with a fuse as a memoryfor holding information regarding the print head.

However, depending on the configuration of the memory mounted on theelement substrate, it is conceivable that unintentional access to thememory may occur due to residual charge. In that case, there is concernthat information cannot be appropriately stored.

SUMMARY OF THE DISCLOSURE

The present disclosure can cause an element substrate to storeinformation appropriately.

Aspects of the present disclosure are related to a control deviceincluding an element substrate and a controller. The element substrateis provided with a fuse memory configured to store information inresponse to having a voltage applied thereto, a first switch configuredto switch whether or not to energize the fuse memory, a resistanceelement, a second switch configured to switch whether or not to energizethe resistance element, a first node connected to the fuse memory andthe resistance element, and a second node configured to supply power tothe first node from outside. The controller is configured to switch thefirst switch, store information into the fuse memory, and read outinformation from the fuse memory. Before allowing the first switch toenergize the fuse memory, the controller causes electric charge thatremains at the first node to be discharged by allowing the second switchto energize the resistance element from the first node.

Further features of the present disclosure will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view mainly illustrating a schematicconfiguration of a print unit of an image printing apparatus accordingto an embodiment.

FIG. 2 is a diagram for describing a print head according to the presentembodiment.

FIG. 3 is a block diagram illustrating the configuration of the printingapparatus according to the embodiment.

FIG. 4 is a flow chart illustrating the procedure of control processingaccording to the embodiment.

DESCRIPTION OF THE EMBODIMENTS

In the following, an embodiment of the present disclosure will bedescribed in detail with reference to the drawings.

FIG. 1 is a perspective view of the configuration of the inside of aninkjet printing apparatus according to the embodiment. In FIG. 1, aninkjet printing apparatus 100 includes an automatic feeding unit 101, aconveyance unit 103, and a recovery unit 108. The automatic feeding unit101 automatically feeds recording media such as paper into the main bodyof the inkjet printing apparatus 100. The conveyance unit 103 guidesrecording media sent one at a time from the automatic feeding unit 101to a certain printing position using a roller and also guides eachrecording medium from the printing position to a discharging unit 102.

The recovery unit 108 performs recovery processing on a print unit thatperforms desired printing on the recording medium conveyed to theprinting position. The print unit includes a carriage 105 and a printhead 201. The carriage 105 is held by a carriage shaft 104 so as to bemovable in main scanning directions represented by an arrow X. The printhead 201 is installed in the carriage 105 so as to be detachable fromthe carriage 105.

The carriage 105 has a carriage cover 106 and a head set lever 107. Thecarriage cover 106 engages with the carriage 105 and is used to guidethe print head 201 to a certain mounting position on the carriage 105.The head set lever 107 engages with a tank holder of the print head 201and presses the print head 201 such that the print head 201 is set atthe certain mounting position.

A head set plate (not illustrated) is provided above the carriage 105 soas to be rotatable about a head set lever shaft, and is spring urged bya portion engaging with the print head 201. The head set lever 107 isconfigured to mount the print head 201 onto the carriage 105 whilepressing the print head 201 with the spring force.

FIG. 2 is a diagram for describing the print head 201 according to thepresent embodiment. The print head 201 engages with the carriage 105 toperform printing. The print head 201 is used in the form of a unithaving printing element columns corresponding to respective liquid inksstored in an ink cartridge 202. The ink cartridge 202 stores inks suchas black (Bk), cyan (C), magenta (M), and yellow (Y) separately fromeach other, and has containers corresponding to the respective colorsand formed so as to be integrated with each other.

The print head 201 according to the present embodiment has, on the sidefacing the recording medium, printing element columns 203 correspondingto the respective colors described above on a one-to-one basis (a columnA in FIG. 2). In FIG. 2, for convenience' sake, only a printing elementcolumn corresponding to one of the colors is illustrated. The printingelement columns 203 are provided on a printing element substrate of theprint head 201, the printing element substrate being formed of amaterial such as silicon. The X direction in FIG. 2 is a “main scanningdirection”, which is the same as one of the directions represented bythe arrow X in FIG. 1. The Y direction is a “sub-scanning direction”crossing the X direction, and is a direction in which the conveyanceunit 103 in FIG. 1 conveys recording media. Each printing element column203 has a plurality of printing elements 204 aligned in the Y direction.The printing elements 204 serve as elements that generate energy used todischarge liquid. The printing elements 204 are electro-thermalconverters and are aligned along the Y direction. Bubbles are caused inink using heat generated by the electro-thermal converters, and ink isdischarged from discharge ports corresponding to the printing elements204 onto the recording medium. Each printing element column 203 of theprint head 201 is used to perform printing for one color component. Theprint head 201 performs printing onto the recording medium bydischarging ink in accordance with the timing of movement while movingin the X direction.

FIG. 3 is a block diagram illustrating electrical configurations of theinkjet printing apparatus and the print head according to theembodiment. A main controller 380, which is a controller of the inkjetprinting apparatus 100, includes a central processing unit (CPU) 381, arandom access memory (RAM) 383, and various circuits and interfaces. TheCPU 381 executes a program read from a read-only memory (ROM) 382. TheRAM 383 temporarily stores information. From a Heater Board (HB) drivecircuit 385, a clock signal (CLK), a data signal (DATA), and a latchsignal (LATCH) are sent to a main controller 353 of a printing elementsubstrate 300 via a connection unit. The clock signal (CLK) is used todrive circuits and elements provided on the printing element substrate300. An antifuse to be described below can also operate using thesesignals. Moreover, these signals include a signal generated by theprinting apparatus on the basis of input image data and used to drivethe printing elements 204. The printing element substrate 300 receives apower supply voltage of 24 V from the inkjet printing apparatus 100 viaa terminal. Furthermore, as will be described later, the inkjet printingapparatus 100 also serves as a device that controls the printing elementsubstrate 300, and causes the printing element substrate 300 to performa write operation and a read operation. In the write operation, anantifuse is caused to store information. In the read operation, thestored information is read out.

Note that the printing element substrate 300 is provided with theprinting elements described above with reference to FIG. 2; however,illustration of the printing elements is omitted in FIG. 3.

Moreover, antifuses are mounted as fuse memories on the printing elementsubstrate 300 of the print head 201. The antifuses are realized bycapacitive elements. Antifuses 341 and 342 are initially electricallyopen and have a substantially infinite resistance. The antifuses 341 and342 are devices the resistances of which are reduced by having a voltageapplied to the antifuses 341 and 342. An operation in which a voltage isapplied to an antifuse to reduce its resistance value so to storeinformation is referred to as a write operation. An operation in whichthe resistance value of an antifuse is confirmed so as to read outinformation is referred to as a read operation. Note that informationthat the antifuses are caused to store is information regarding, forexample, the print head 201 and is used as a parameter for the inkjetprinting apparatus 100 to control the print head 201.

For the antifuse 341, a switch (SW) 331 and a SW 351 are provided. Forthe antifuse 342, a SW 332 and a SW 352 are provided. These switches canbe used to switch whether or not the antifuses can be energized.

When the read operation is to be performed on one of the antifuses, inresponse to a command from the CPU 381 included in the main controller380 of the inkjet printing apparatus 100, serial communication to thecontroller 353 included in the print head 201 is performed using aserial communication signal generated by the HB drive circuit 385.Content received by the controller 353 includes information indicatingthat a read operation mode is to be started and information forselecting an antifuse to be subjected to the read operation. In a casewhere the selected antifuse is the antifuse 341, the CPU 381 switches onthe SW 331 through serial communication. Next, the CPU 381 switches onthe SW 351. In the present exemplary embodiment, at the time of the readoperation mode, the DATA signal is connected to the SW 351. When a SW321 is switched on in this state, electric charge is generated at a node312, which is a wiring line from the SW 321 to the SW 331, the SW 332, .. . , due to a current from a constant current source 322. A comparator323, which compares this electric charge with reference electric charge,outputs information regarding whether the resistance value of theselected antifuse 341 is greater or smaller than a reference resistancevalue. The CPU 381 included in the main controller 380 can acquire, as abinary value, the signal output from the comparator 323 via ageneral-purpose input/output (GPIO) 384, which is an output destinationof and is connected to the comparator 323 by a signal line. After theread operation is completed, the CPU 381 performs serial communicationto switch off the SW 351. Moreover, the CPU 381 performs serialcommunication to switch off the SW 331.

When the write operation is to be performed on one of the antifuses,serial communication from the main controller 380 to the controller 353provided on the printing element substrate 300 is performed using aserial communication signal generated by the HB drive circuit 385.Content received by the controller 353 includes information indicatingthat a write operation mode is to be started and information forselecting an antifuse to be subjected to the write operation. In a casewhere the selected antifuse is the antifuse 342, the CPU 381 switches onthe SW 332 using an antifuse selection signal. Next, by switching on aSW 311, the CPU 381 supplies power necessary for the write operation tothe node 312 via a node 313 from outside the printing element substrate300. When the SW 352 is switched on in a state in which power issupplied to the node 312, the resistance value of the antifuse 342 canbe reduced. In the present embodiment, at the time of the writeoperation mode, the DATA signal is connected to the SW 352. In a casewhere it is less likely that the resistance value of the antifuse 342reaches a desired resistance value after the SW 352 is switched on onlyone time, on-to-off and off-to-on operations are repeatedly performed onthe SW 352 a plurality of times. After the write operation is completed,the CPU 381 switches off the SW 352. Moreover, the CPU 381 performsserial communication to switch off the SW 332.

Combinations each including an antifuse, a SW on the node side, and a SWon the controller side are arranged in addition to a combination of theantifuse 341, the SW 331 on the node side, and the SW 351 on thecontroller side and a combination of the antifuse 342, the SW 332 on thenode side, and the SW 352 on the controller side.

A resistance element 340 is provided, which is connected to a SW 330connected to the node 312 and is connected to a SW 350 on the controllerside. The resistance element 340 is used to discharge electric charge ofthe node 312. The SW 350 is also connected to ground. Note that theresistance element 340 is also used in measurement for examining theresistance values of other resistance elements provided on the printingelement substrate 300.

FIG. 4 illustrates a flow chart illustrating the procedure of processingin the read operation and the write operation using the inkjet printingapparatus according to the embodiment illustrated in FIG. 3.Hereinafter, description will be made with reference to FIGS. 3 and 4.The processing illustrated in FIG. 4 is set to be executed at a certaintiming. For example, the processing is performed when the inkjetprinting apparatus 100, which is not connected to a power supply, isconnected to an AC power supply and also at a timing at which access toone of the antifuses needs to be made after the inkjet printingapparatus 100 is connected to the power supply.

First, in step 450 illustrated in FIG. 4, the CPU 381 determines whetheror not to discharge the node 312. Step 450 is performed, for example,when the inkjet printing apparatus 100 is connected to an AC powersupply for the first time. In this case, the CPU 381 determines that thenode 312 is to be discharged, and Yes is obtained. In contrast, in acase where access to any one of the antifuses has been made a pluralityof times after the inkjet printing apparatus 100 is connected to the ACpower supply, and the CPU 381 determines that the node 312 does not needto be discharged, the process proceeds to step 400.

In a case where Yes is obtained in step 450, the process proceeds tostep 451, and the CPU 381 switches on the SW 330 and the SW 350. As aresult, the electric charge of the node 312 is discharged by the effectof the resistance element 340. The electric charge of the node is notoutput to outside the printing element substrate 300, and thus, forexample, when power supply to the printing apparatus is blocked in astate where a voltage is applied to the node 312 from the power supply,the electric charge of the node 312 is not consumed and stays there asresidual charge. However, in a case where the electric charge of thenode 312 is discharged in this manner, this can help to prevent, forexample, the residual charge of the node 312 from flowing into theselected antifuse 341 and unintentionally executing the write operationwhen the SW 331 and the SW 351 are switched on.

Next, the process proceeds to step 452, and the inkjet printingapparatus 100 waits for a predetermined time since it takes time todischarge the electric charge of the node 312 due to parasiticcapacitance and the resistance value of the resistance element 340.

Next, in step 453, the CPU 381 switches off the SW 330 and the SW 350.

Through the operation described above, the discharge of the node 312 iscompleted, the potential of the node 312 can be made equal to ground,and the inkjet printing apparatus 100 can be reset to its initial state.

In steps 400 and 402, in response to a command from the CPU 381 includedin the main controller 380, serial communication to the controller 353provided on the printing element substrate 300 is performed using aserial communication signal generated by the HB drive circuit 385.Content received by the controller 353 includes information indicatingthat the read operation mode is to be started and information forselecting an antifuse to be subjected to the read operation. The CPU 381selects an antifuse in this manner and switches on a SW 33X (X is aninteger) connected to the selected fuse. In this case, suppose that theselected antifuse is the antifuse 341, and the CPU 381 switches on theSW 331 through serial communication (step 400). Furthermore, asdescribed above, the CPU 381 selects the read operation mode and sendscontent to the controller 353, the content including informationindicating that the read operation mode is to be started (step 402).

In the case of the read operation, the process proceeds to step 421, andthen the CPU 381 switches on the SW 35X (X is an integer), which is theSW 351 in this case. In the present embodiment, the DATA signal isconnected to the SW 351 at the time of the read operation mode.

Next, when the SW 321 is switched on in step 422, electric charge isgenerated at the node 312, which is a wiring line from the SW 321 to theSW 331, the SW 332, . . . ,due to an electric current from the constantcurrent source 322.

In step 423, the comparator 323, which compares the electric charge ofthe node 312 with reference electric charge, outputs informationregarding whether the resistance value of the selected antifuse 341 isgreater or smaller than a reference resistance value. The CPU 381included in the main controller 380 acquires, as a binary value, thesignal (an output result) output from the comparator 323 via the GPIO384, which is an output destination of and is connected to thecomparator 323 by a signal line.

In step 424, the CPU 381 performs serial communication to switch off theSW 321.

In step 403, the CPU 381 performs serial communication again to switchoff the SW 331.

Furthermore, the CPU 381 switches off the SW 351.

In a case where the CPU 381 selects the antifuse 342 in step 400 andselects the write operation in step 402, the CPU 381 performs serialcommunication to the controller 353 provided on the printing elementsubstrate 300 using a serial communication signal generated by the HBdrive circuit 385. Content received by the controller 353 includesinformation indicating that the write operation mode is to be startedand information for selecting an antifuse to be subjected to the writeoperation. In a case where the selected antifuse is the antifuse 342,the SW 332 is switched on based on antifuse selection information fromthe CPU 381.

In step 411, by switching on the SW 311, the CPU 381 applies a voltageVcut necessary for the write operation to the node 312.

Next, in step 412, the CPU 381 switches on the SW 352.

In step 413, the resistance value of the antifuse 342 is reduced. Infollowing step 414, the CPU 381 performs serial communication to switchoff the SW 311.

Next, in step 403, the SW 332 is switched off.

According to the embodiment, it is less likely that unintentional accessto a memory of an element substrate occurs due to residual charge, andinformation can be appropriately stored.

OTHER EMBODIMENTS

The embodiment of the present disclosure can also be realized by acomputer of a system or apparatus that reads out and executes computerexecutable instructions (e.g., one or more programs) recorded on astorage medium (which may also be referred to more fully as a‘non-transitory computer-readable storage medium’) to perform thefunctions of one or more of the above-described embodiment and/or thatincludes one or more circuits (e.g., application specific integratedcircuit (ASIC)) for performing the functions of one or more of theabove-described embodiment, and by a method performed by the computer ofthe system or apparatus by, for example, reading out and executing thecomputer executable instructions from the storage medium to perform thefunctions of one or more of the above-described embodiment and/orcontrolling the one or more circuits to perform the functions of one ormore of the above-described embodiment. The computer may comprise one ormore processors (e.g., central processing unit (CPU), micro processingunit (MPU)) and may include a network of separate computers or separateprocessors to read out and execute the computer executable instructions.The computer executable instructions may be provided to the computer,for example, from a network or the storage medium. The storage mediummay include, for example, one or more of a hard disk, a random-accessmemory (RAM), a read only memory (ROM), a storage of distributedcomputing systems, an optical disk (such as a compact disc (CD), digitalversatile disc (DVD), or Blu-ray Disc (BD)), a flash memory device, amemory card, and the like.

While the present disclosure has been described with reference toexemplary embodiments, it is to be understood that the disclosure is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of priority from Japanese PatentApplication No. 2021-040994, filed Mar. 15, 2021, which is herebyincorporated by reference herein in its entirety.

What is claimed is:
 1. A control device comprising: an element substrateprovided with a fuse memory configured to store information in responseto having a voltage applied thereto, a first switch configured to switchwhether or not to energize the fuse memory, a resistance element, asecond switch configured to switch whether or not to energize theresistance element, a first node connected to the fuse memory and theresistance element, and a second node configured to supply power to thefirst node from outside; and a controller configured to switch the firstswitch, store information into the fuse memory, and read out informationfrom the fuse memory, wherein, before allowing the first switch toenergize the fuse memory, the controller causes electric charge thatremains at the first node to be discharged by allowing the second switchto energize the resistance element from the first node.
 2. The controldevice according to claim 1, wherein the electric charge of the firstnode is not output to outside the element substrate.
 3. The controldevice according to claim 1, wherein in a case where electric chargethat remains at the first node is discharged, the resistance element isconnected to ground.
 4. The control device according to claim 1, whereinthe element substrate is provided with a plurality of the fuse memoriesand a plurality of the first switches corresponding to the plurality offuse memories.
 5. The control device according to claim 1, wherein theresistance element is also used to measure resistance values of otherresistance elements in the element substrate.
 6. The control deviceaccording to claim 1, wherein the element substrate is provided so as tocorrespond to a liquid discharge port and is a printing elementsubstrate provided with a printing element configured to generate energyto be used to discharge liquid.
 7. The control device according to claim6, wherein the controller sends a signal for driving the printingelement to the printing element substrate, the signal being based oninput image data.
 8. A method for controlling an element substrateprovided with a fuse memory configured to store information in responseto having a voltage applied thereto, a first switch configured to switchwhether or not to energize the fuse memory, a resistance element, asecond switch configured to switch whether or not to energize theresistance element, a first node connected to the fuse memory and theresistance element, and a second node configured to supply power to thefirst node from outside, the method comprising: discharging, beforeallowing the first switch to energize the fuse memory, electric chargethat remains at the first node by allowing the second switch to energizethe resistance element from the first node.